We have a pass code where I work that allows us to get keys from boxes to various buildings. each person has a code that allows them into any key box. I used my code every day, in fact every few minutes through out the day. One day I got a key out of a box, went into the building for just a couple of minutes and when I came out to return the key I could not remember the code I had just used a couple of minutes before. I stood there waiting for the brain cell that contains that data to wake up for several minutes but never was able to remember the code. I finally had to go to our Lock Shop that keeps all the codes on file and have them tell me my code again. I have not had the problem again since. but it was the weirdest thing. and like you say pretty scary. I have seen a doctor since then and have a clean bill of health but still I am certain they are only missing something. It really is like some portion of my brain just stopped working.